Earth boring bit with protected seal means
US5129471A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 31, 1991 |
| Grant date | Jul 14, 1992 |
| Priority date | — |
| Expiry date | May 31, 2011 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16J15/3456
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
An earth boring bit having a body, pressure compensating lubricating system and cantilevered bearing shaft with an annular seal surface and a radial seal surface. A cutter is rotatably secured to the bearing shaft, with an annular seal recess having radial and cylindrical seal surfaces to oppose the seal surfaces on the body and bearing shaft to define a seal gland. A resilient and annular packing ring is compressed between the cylindrical seal surfaces, but has a length less than the minimum length of the gland. A shroud extends inwardly near the outer backface a selected distance behind the packing ring to bias it inwardly. The shroud extends inwardly toward the bearing not more than about 30% of the cross-sectional thickness of the O-ring in the relaxed condition. The O-ring is compressed in a range of about 10 to 15 percent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.